From mystery novels to superheroes to rappers, this edition of Dens Around the World is a mixed bag.
1. Secret Room
![Secret bookcase with single angled book](https://mancaveinsider.com/user/pages/05.blog/dens-around-the-world-002/01.book-secret-door.jpg)
In true Scooby-Doo fashion, the entrance to this man cave is through an inconspicuous bookcase. Pull on volume 17 of The Hardy Boys Mystery S...